The Corvette in Myth and Legend

Here are some prevailing myths on the small warship which New Wars advocates as the antidote to much of the naval woes affecting Western navies in the modern era. These include shrinking numbers of high end warships which typically end up being used in low tech warfare, against pirates and smugglers or speed boat fleets like Iran. Such high end vessels continue to rise in price, are notorious fuel hogs for an increasingly energy conscious military, and require huge manning to maintain. The answer to the latter has been to increase automation which further adds to the price without necessarily making things better for now smaller but overworked crewman.

While becoming more and more capable, the large multimission warship hasn’t provided us with the answers we need for modern problems of seapower. They often add to our difficulties by making enormous demands on shipbuilders to build ever fewer hulls, which are very complicated, requiring enormous expertise to design. Not surprisingly such technically complicated vessels enter the fleet unfinished, riddled with faults, requiring numerous returns to the dock for repairs. Most notoriously this has occurred with the LPD-17 class amphibious ship, and seems also to be the fate with the Navy’s presumed answer to high end warships, the $600 million+ LCS.

The navy claims only high end, very large, and technically complicated warships will do for its future needs. While continuing to suffer from over-deployments and presence deficits, it rejects low cost alternatives, small warships in the employ of small navies the world over. They are immediately shocked at the notion that a speed boat, fast attack craft, or corvette could ever perform the same mission as one of their billion-dollar battleships, yet these same vessels are being used by rogue nations to threaten historical Western sea dominance, because of our diminishing number of resources.

Below then we present several excuses advocate of Big Ships only use to vilify the very type of vessels that might be the answer to all their current problems, the corvette:

Small warships are too vulnerable

German Braunschweig corvette. Author Torsten Bätge

Sadly we have gotten to the point where we consider hull size as power and effectiveness. In some cases this is true, but you must have some balance. The ship needed for the Blue Water of necessity should be large, that is common sense. But a craft meant to fight in shallow water, close to many threats from air, sea, and land, should naturally be small offering a smaller target, or natural stealth. Because threats are so many, you would also require a great many to overwhelm defenses, plus ensure individual ships more survivability. The smaller hull would be cheaper(though not necessarily cheap), require smaller manning the Navy is seeking, and more fuel efficient, also a plus today.

Corvettes are poor sea-keepers

I often use the example of small warships utilized in the Battle of the Atlantic, plus the Pacific Campaign, concerning corvettes and seakeeping. Some contend that corvettes and patrol vessels are totally inadequate for littoral warfare, despite the fact they were also used to combat this very serious threat on the high seas. They are exactly the same size as the escorts from the war years, that did very well on the high seas. The 800 ton Flower corvettes were about the limit you would want to sail in the stormy North Atlantic. They were very lively, to say the least, though Churchill dubbed them “cheap but nasties”. The larger sloops and frigates, from 1200-1500 tons solved many of the inadequacies of the Flower class, and were much better sailer’s.

An alternative which can produce a very stable platform without a large hull is SWATH technology. DK Brown described this capability in his book The Future British Surface Fleet:

SWATH stand for Small Waterplane Area, Twin Hull. Such vessels have two deeply submerged cylindrical hulls connected by narrow struts to a platform well above the water surface. The submerged hulls are little affected by most waves which leave the platform level, dry, and undisturbed. In the most severe seas, the SWATH will follow the wave surface with motions still much less vigorous than those of a conventional ship.

In waves, the SWATH will be able to maintain speed better than a conventional ship and because it is much steadier, it is able to operate sensors, weapons, and helicopters when others cannot…The US experimental SWATH, Kaimolino. of only 200 tonnes, has shown seakeeping comparable with that of a 2500-tonne monohull sailing in company. Technically. SWATH is a well-proven concept.

Naturally, the larger 3000-5000 ton frigates of today are roomy and comfortable. I think they pay the price for their immaculate accommodations by being far more expensive and thus greatly fewer in number. The frigates of today stay at sea far longer than did the escorts of the war years, for all their capability. They are wonderful sailer’s, but seem to have lost the point of a warship, which is “a ship built to fight”. We see the worse aberration of this in the LCS.

They are too poorly armed to contend with high end ships

In some cases this is true, but many corvettes are as well armed as modern frigates, and all better so than the LCS! As we wrote in 2009…the corvettes of today are not the fast attack craft (FAC) of 20-30 years ago, the first generation of missile boats. Newer craft like the UAE’s Baynunah and the German Braunschweig come heavily armed with missiles, guns, and even helicopters. The more advanced ships come with sophisticated surface to air defenses, like the Evolved Sea Sparrow or the Sea Ram missiles. Many like the Maylasian Kedah carry the Oto Melara 76 mm Super Rapid gun, which is heavier than the 57 mm carried by the frigate-sized LCS. Most, like the Sigma class for Indonesia carry a small Sonar suite, something the heavier and more expensive USS Freedom also lacks!

So when thinking of corvettes for Western navies, think of Germany and Israel, not Iran and Iraq!

Small warships are fodder for helicopters

There are problems with this recurring excuse against Western deployment of corvettes and fast attack craft. First off, it seems to ensure continued production of fewer but very expensive and hard to replace large surface combatants, with the notion “we have no choice”. Except, advances in technology must happen and there are always alternatives.

The sinking of the Israeli destroyer Eilat in 1967 by Egyptian missile boats is often considered the dawn of the cruise missile age. A key decision by the Jewish Navy led to their discarding of all large warships for an-all small warship Navy consisting of Sa’ar class attack craft, also armed with cruise missiles such as the home-built Gabriel. These were very successful in the 1970s with the destruction of Egyptian craft, and leading to the domination of the coastal regions by Israel ever since.

This is proof that a nation can operate a force of corvettes which can be very effective and cost effective, especially in the presence of their own supreme air superiority, something the Western fleets rarely ever leave port without. Likewise have new tactics such as swarming, and increased miniaturization of warfare with sensors and weapons allow drastically less room for extremely advanced weapons to counter enemy air threats.

Another factor in the need for many small warships can be taken from the first paragraph of this particular question. Because of shrinking number of high end assets, small boat navies may actually win by being where the frigates and destroyers aren’t. For instance, it should be noted the fleets of America and the UK which effectively used helicopter anti-small boat tactics in the Falklands and in the various Gulf Wars, are about half the size they were during these conflicts of the 1980s and 1990s. Each are expected to shrink further in coming decades, which is already leaving gaps that small boat navies, like Iran with an estimated 1000 in service, to exploit.

The falling ship numbers brings us back to our central reason for building the corvette, so that Western navies do not vanish under the weight of their own cost. As Secretary Gates pointed out so clearly, we can’t continue building costing many billions, or even frigates which price nearly so, and expect to have effective fleets in the future. Ships which are individually very capable, but cannot be where you need them to be in a crisis, or bring undue strain on sailors, are no longer adequate for our needs. Neither have large ships ever safely operated in shallow waters very long without escort from small warships, a crucial lesson from the World Wars we seem to have forgotten.

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Mike Burleson said : ” The inflated specifications for the perfect vessel means you have more luxury combat ships today than real warships.”

The recurring theme of how today’s corvettes are *about the size of frigates and destroyers in WW2* reminds me of what the much regretted DK Brown wrote in his “Nelson to Vanguard” on the subject of human factors in the chapter dedicated to Escorts (p. 134) :

“Today, it is recognized that the combat efficiency of the crew is increased if they are well fed and can rest properly when off duty but this was not recognized during the war and British ships fell well short of what was possible and desirable. There was an impression that sailors were tough and almost revelled in discomfort; in particular, it was thought that discomfort was necessary to keep men awake when on duty.”

IOW, crew comfort, far from being a luxury, is actually paramount to the combat efficiency of a WARship, and is therefore the kind of critical attributes that a Navy meant to fight should not compromise with !!!

Additionally, note what the weapon had been used to sink the former Canadian destroyer HMSC HURON three years ago. There were nothing heavier than Sea Sparrow missile and 76-mm shells from her own gun, installed on the sistership HMCS ALGONQUIN. The scenario of the TRIDENT FURY operation had included the fictive supposition that the ship had been previously captured by the terrorists, and no decisive weapon such as sea-skimmers had been used to fire. Moreover, all the artillery shells and SAM had been fired maximally carefully, to hit the selected areas of the hull and superstructure.
If such a scenario of the sea battle had been presented by the Canadians, whether it means that this kind of scenario is in detailed consideration by the major navies? If so, the LCS ‘s clear strike weakness is no more than the typical armament for such a circumstances.

You are right, but if the AEGIS-ship doesn’t present in the area? You know, the Swedish and Finnish navies (hardly one’s efforts to find the more “corvette” navies will be successful) are extremely concerning by the effective compact SAM solutions so they found the South Africans with their Umkhonto-IR missiles. Unusual quite for the naval SAM, infrared seeking version not only lighter but also free from the common for semi-active radar systems targeting radar radiation, that is the way to make the launching ship more stealthy.

Plus you have Sea Sparrow, which is a better fit for a corvette. There is a Spy-1K small enough to fit on a small warship. This is Aegis-lite.

If there is already an Aegis frigate or destroyer in the area, you would not need an advanced system on the small warship. These ships also do command and control like floating AWACS and could target the corvette’s missiles without the expensive and heavy addition of phased array radar.

The first key point is that how soon the RBS-15 will fly over the 1000 km range and how precision this weapon will be? All the sea-scimmers, the main weapon of the Corvette Navies, are now drifting to cruise missile’s task to be used against the land targets. But how succesful such a usage will be, is unclear.
The second key point is the SAN abilities. Speaking striclty, the corvette could replace frigates and destroyers nit until the SAM means onboard could maintain the same air defence level that Standard (SM-2) or S-300 are demonstrating.
In other words, let the missiles of the the corvettes do the same that missiles of the FFG-DDG-CG can do, and the Corvette Navy will become actual.

Corvettes (1,000-1,5000T) can mount the same weapons as small frigates… such as ESSM/CAMM, Harpoon and a 4.5/5″ gun…

Small corvettes also cost almost the same as a larger counterpart(K130 is a perfect example) if you start welding the same weapons platforms to the decks that you do on your small frigates, and require more support vessels, a 1,500T corvette isn’t going to have a range of any larger than about 3,000nm and they require additional RAS vessels to be procured

ArkadyRenko said : “First of all: you advocate going to a Corvette dominated navy. Where is your air cover going to come from? The aircraft carriers you have dismissed as being too expensive? How are the Corvettes going to refuel and rearm? By large fleet auxiliaries, which will be the primary target of your opponent. Switching to Corvettes will increase the logistical burden in any expeditionary role. Which means more ships will be needed to guard the logistical supply line.”

Mike Burleson said : “I was only saying we may have to choose whether we want a fleet of Luxury Combat Ships, or a large navy.”

A large navy can be had without corvettes. In fact, corvettes would unquestionably be the worse investment in terms of taxpayer dollar and the most suicidal option for the life of our sailors and warfighters.

A large navy can be had without corvettes. All you have to do is THINK BIG, not small.

Mike Burleson said : “But a craft meant to fight in shallow water, close to many threats from air, sea, and land, should naturally be small offering a smaller target, or natural stealth.“

As a matter of fact, leaving aside the basic fact that relying exclusively upon stealth for survival is a losing proposal, it can be argued that a greater size is of considerable help with some aspects on stealth, e.g. silencing or IR signature reduction.

Bottom line is that this *Natural stealth* thingy is 100% BOGUS : nothing more than yet another buzzword in the Naval Newspeak.

That Russian corvette is a surface effect ship, not a hovercraft. Just for the record. ;-)

The ‘complex control systems’ for a SWATH being referred to as some kind of detrimental or negative feature is total crap; a red herring thrown out by someone who knows nothings of what they speak of. Nearly lll modern ‘corvette sized’ vessels, and smaller, (i.e those that are owned/operated by any other Navy but our own) incorporate exactly the same equipment. The stabilization package on the new USCG FRCs is nearly identical to that on the SWATH in the video that is the highlight of the blog post next to this one. The only difference is essentially the software..the SWATH system will incoroporate the sensors and control algorithms for concurrent pitch and roll control (and, quite often, yaw and bow height control too)but its all the same fin and servo hardware otherwise.

“Corvettes of 1000-1500 tons can mount the same weapons as larger destroyers and frigates,”

Which :

1) Is NOT true.

2) Completely misses the crucial point that the mythical corvette lags behind even further when it comes to sensors…

The importance of sensors has been discussed several times in the past, for instance to explain the complete failure of the Iraqi FACs during the infamous Bubiyan Turkey Shoot.

Here is what Stuart Slade wrote on the subject in Friedman’s Navies in the Nuclear Age (p.106) :

“The failure of the FAC-M as a naval equaliser capable of offsetting the power of conventional warships was utter and complete. A share of the extent of the Iraqi disaster can be explained by the poor material condition of their boats and the abysmal training standards of their crews.

However, once these factors have been discounted, the fact remains that the fundamental reasons for the defeat of the FAC-Ms are inherent in the design of the craft and cannot be eradicated.

Firstly, the lightly-built FACs vibrate too much as a result of the powerful engines installed and their rough ride in anything other than mill-pond conditions. This causes the tracking beams on the air defense fire control radars to wander off target before a firing solution can be attained.

Secondly, the low silhouette of the boats, essential for their role, means that radars and equipment have to be carried low. This limits their maximum coverage against low-flying targets.

To make matters worse, the low mountings mean that the electronics are within the surface duct, a layer of warm, moist air trapped close to the sea surface. Radars and ESM equipment within this duct cannot detect targets flying above it.

There is another disadvantage associated with radars carried low; the radar beam travels directly to its target but also reflects off the sea surface to the target and off the top of the surface duct to the target. This multi-pathing effect provides a series of ghost images with the radar fire control oscillating helplessly between them.”

On the issue of small boats operating in stormy coastal waters, consider the record of the German S-boats (Schnellboot, known to tha Allies as E-boats, in WWII.) I don’t know how uncomfortable they were or how many were lost to rough seas, but they certainly rang up an impressinve total of enemy ships and boats sunk during the war in stormy northern seas. Specs: 100t, 32.76m length.

“During their operational history in World War II, the S-boote sank 101 merchant ships totalling 214,728 tons.[8] In addition, they sank 12 destroyers, 11 minesweepers, eight landing ships, six enemy MTBs, a torpedo boat, a minelayer, one submarine and a number of small merchant craft. They also damaged two cruisers, five destroyers, three landing ships, a repair ship, a naval tug and numerous merchant vessels. Sea mines laid by the ‘S-boote’ were responsible for the loss of 37 merchant ships totalling 148,535 tons, a destroyer, two minesweepers and four landing ships.[9]

In recognition of their service, the members of Schnellboot crews were awarded the Knight’s Cross 23 times, and the German Cross in Gold 112 times.[10]” Wiki

Scott, I don’t think I was trying to disguise the seakeeping qualities of the corvette versus frigates. I was only saying we may have to choose whether we want a fleet of Luxury Combat Ships, or a large navy. I don’t think we can have both, but I do think we can manage a fleet of corvettes, since we did so with vessels of the same size previously, when they were called frigates and destroyer escorts.

Also notice I pointed out technologically we probably can have both, affordable ships and good seakeeping.

It would be nice to keep all our space-age wonder ships, if it wasn’t for the presence deficits and gaps we get, from over-spending and under-building.

Smitty, most sources I have looked at say the Type 22 is SWATH including this from China Defense:

“One photo from Chinese Internet has proved that the Kamewa waterjets have been installed on the Type 022 missile craft, which features a wave-piercing catamaran hull design known as Small Waterplane Area Twin Hull (SWATH).”

Arkady, I don’t think I said we should have corvettes instead of aircraft carriers. I have previously written we have too much airpower, and not enough ships to maintain control. It’s nice to have command of the air, but if you have nothing to control what you already command, the enemy slips through your net. the pirates do this consistently, and we have plenty of air capable ships there.

So, you need a flotilla for control. Concerning logistics, the small ships utilize drastically less fuel individually than giant battleships, and certainly less than glorified speedboats like LCS. I don’t think the logistics problem would be any more than previously when we deployed a 600 ship navy. We also use naval ports now, what would change?

As MatR pointed out, the corvettes would be gap fillers, working alongside the larger ships, extending their capabilities, going where the Big Ships can’t, or probably shouldn’t in the missile age. We can’t afford enough large hulls, not nearly as many as we need. The small ships enhances the Navy, it does not weaken it as has our current procurement practices.

“Speed performance in smooth water is determined by the size and shape of the underwater hull, principally, at the speeds of frigates and destroyers, by waterline length. (…)

The sea resists the passage of a ship by a combination of friction and wavemaking (residual) resistance; the latter is very largely a function of the speed-length ratio. (…)

Again, very crudely, power required per ton is very nearly a function only of the speed-length ratio, since frictional influences follow much the same trend as residual ones.”

And Norman Friedman to observe (p. 65) that :

“On the other hand, to maintain 30 knots in Sea State 4 (which was the Spruance design requirement) is far more difficult to achieve than the pre-war 36 knots in smooth water : although modern destroyers and frigates appear (on paper) rather slow in comparison to their forebears, their effective speeds are rather better. This speed, however, is often bought largely by better (and larger) hull forms, rather than by more power per ton or per cubic foot.”

To finally conclude :

“The weights of equipment which must go into the ship habe proportionately less impact on a larger hull, which, among other virtues, is easier to propel at high speed and likely to be more seaworthy.”

Mike Burleson said : “They are wonderful sailer’s, but seem to have lost the point of a warship, which is “a ship built to fight”.”

Another SERIOUS misconception, as was explained so many times previously on this blog, for instance July 2009 :

*****************************************************************
Seakeeping and crew comfort are not just *leisurely peacetime requirements* as you suggest.

For instance, below are a couple of short paragraphs from STANAG 4154, Common Procedures for Seakeeping in the Ship Design Process :

“The general desirability of good seakeeping performance is universally accepted and has been for almost as long as ships have been designed and built. In general terms, good seakeeping qualities permit a warship to operate in adverse weather conditions with minimum degradation of mission effectiveness.“

AND

“despite the clear link between poor seakeeping and reduced mission performance, seakeeping is not given sufficiently high priority when the naval requirements are defined.”

Mike Burleson said : “A lot of the complaints I get from skeptics of the small corvette idea often proposed here, is the poor seakeeping qualities of such vessels. Aside from the fact that ships geared toward shallow water warfare have little need of Blue Water abilities“

FALSE

This is actually a gross misconception, as the defunct D.K. Brown pointed out so many times, for instance in his “Future British Surface Fleet” (p.56) :

“It is widely believed, incorrectly, that waters close to the land are sheltered and so are safer, but even in the English Channel high winds and seas are not uncommon.

The 50-year wave height is 20 meters almost to the Isle of Wight, with a corresponding wind speed of 30 m/s.

Many inshore disasters have shown the danger of underestimating coastal areas, such as the breaking in half of the French torpedo Boat Branlebas off Dartmouth in World War II.”

As Norman Friedman summarized in his “Modern Warship Design and Development” (p.70) :

“Accounts of wartime corvette operations are filled with examples of ships effectively out of action due to the mountainous seas, but such things rarely occur in accounts of the larger frigates, which operated in much the same areas/”

The poor seakeeping qualities of the mythical corvette have been discussed ad nauseum on New Wars in the past, for instance :

I’d hate to pit a corvette against an aircraft carrier! ;o) But to date, only two countries on earth have carrier aviation with a reach of 1000 nm, and that’s with A2A refuelling. In the future, four nations at most will have that capability, and the Chinese and Indians will probably only have one aircraft carrier each through to 2025. If us pitiable Britons (or Italians, or Spanish, or Japanese) use carriers, our F35s will have short, stumpy little legs ;o)

Corvettes are small, so they hide well in the clutter of the littorals, especially in areas of major sea traffic and convoluted coastlines like the Pacific Rim or Indian Ocean. It’s something the Taiwanese and Scandinavians know they can rely on for their own anti-access strategies – hiding their corvettes amongst complex radar echoes and multiple heat signatures.

In blue water, if you don’t face a carrier and you’re 1000nm from an enemy’s coast, the corvette still has plusses. 90-95% of nations don’t have the land based air assets to reach it that far out. It can carry exactly the same weapons as a 10,000 ton destroyer or 5,000 ton frigate (although not as many of them) but with a vastly smaller signature. You get more of them for your money, so they’re more places at once. And there’s no absolute reason that it can’t carry A2A missiles with a long range. They do have to refuel more often than larger ships, but that’s never stopped corvettes from being used before away from continental shelves.

They’re not perfect, but they’re handy. I’d wager we need more for the kind of fractious, multi-polar world that’s coming, for duties like EEZ patrol, anti-piracy and sub-hunting. Stick UAVs on them, or network them, and I think they’ll have the sensor range of larger vessels – more ‘wolfpack’, less ‘sitting duck’. (I do terrible metaphors for free ;o) )

Your article has a certain slippery quality to it, you failed to address several points.

First of all: you advocate going to a Corvette dominated navy. Where is your air cover going to come from? The aircraft carriers you have dismissed as being too expensive? How are the Corvettes going to refuel and rearm? By large fleet auxiliaries, which will be the primary target of your opponent. Switching to Corvettes will increase the logistical burden in any expeditionary role. Which means more ships will be needed to guard the logistical supply line.

Let me look, in a bit more detail, at your helicopter vs corvette discussion. You said that miniaturization of weapons means that Corvettes will be better equipped to deal with helicopters. That is true. It also means that Helicopters will be better equipped to deal with corvettes. The real threat to Corvettes will be fixed wing aircraft, operating from carriers. Those can fly above most short ranged SAMs. For example, the TOR-M1 has a max altitude of 20k ft. (From wikipedia) You can fly above those Corvettes, and use laser guided bombs. The fighters won’t even need to use advanced missiles. It will become a modern Marianas Turkey Shoot.

The advantage of airpower, which you have completely ignored, is that air planes have much much greater range than Corvette weapons or sensors. Carriers can destroy the Corvettes from a stand off distance, then come in later on. Yes, Carriers won’t work well in confined waters, that is a given. But, when you want to actually fight for control of the ocean, nothing beats the flexibility of carriers.

The question for the US Navy is not: we need a force of Corvettes to charge into littoral waters. The question is: how to we gain presence in the littoral waters, but still maintain the long distance striking flexibility of a Carrier. The Navy could use more hulls, perhaps for the ASW escort role. But, it doesn’t need a force, that can only work in the littoral areas.

Trick question … and I *know* this is going to make some people cringe …

What happens when you merge SWATH type construction with M-Hull shaping above the waterline? Essentially, what happens if each of those FIVE wave piercing waterline points on the hull of a M-60 Stiletto sported a submerged hull to improve seakeeping qualities as sea states increase?

First and most obvious compromise would be the shallowness of the draft, but if you’re driving on water jets you have a minimum shallowness of draft imposed by the impeller intakes anyway (realistically speaking). The second most obvious compromise would probably (probably) by speed, since you’d almost certainly be increasing the wetted area underwater.

By the same token though, you might (might!) be able to raise the entire ship hull above the waterline higher out of the water by about a meter … thereby doing all sorts of things to counter the wave buffeting issue(s) at high(er) speeds.

In case it wasn’t obvious enough already, I *really* have no idea of what I’m talking about here. I’m just wondering out loud in a Tab A + Slot B sort of formulation, trying to figure out what happens if the parts get fitted together. It’d probably be all sorts of *WRONG* to try and do a SWAMH (Small Waterplane Area, M-Hull) instead of a SWATH … but I have to wonder what sorts of hydrodynamics would result.

I also have to wonder if a SWAMH might not work as a hydroplane, with a lift wing(s) between submerged hulls for high speeds.

If you look at the Wikipedia page for SWATH you’ll see some of the drawbacks,

“The main disadvantages of SWATH watercraft are that they are more expensive than conventional catamarans or mono-hulls, require a complex control system, have a deeper draft, and maintenance requirements are higher. Furthermore, SWATH vessels can require up to 80% more power than equivalent catamarans[citation needed], and are more limited in speed compared to equivalent catamaran vessels.“

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